Oriented perforating apparatus



1967 J. B. SHORE 3,338,317

ORIENTED PERFORATING APPARATUS Filed Sept. 22, 1965 3 Sheets-Sheet lJames B. 5/70/6 INVENTOR ATTORNEY Aug. 29, 1967 J. B. SHORE 3,338,317

ORIENTED PERFORATING APPARATUS Filed Sept. 22, 1965 it 4o 3 Sheets-Sheet2 (/c zmes .5 Shore INVENTOR.

// Aria/FIVE Patented Aug. 29, 1967 3,338,317 ORIENTED PERFORATINGAPPARATUS James B. Shore, Friendswood, Tex., assignor to SchlumbergerTechnology Corporation, Houston, Tex., a corporation of Texas FiledSept. 22, 1965, Ser. No. 489,114 17 Claims. (Cl. 1754.51)

This invention relates to preforating apparatus for use inmultiple-completion well bores; and, more particularly, to new andimproved means for orienting such perforating apparatus and preventingits premature actuation until it has been properly oriented relative toadjacent tubing strings and for facilitating the retrieval of theexpended apparatus.

In one technique of completing oil wells having a plurality of spacedproductive earth formations, the well is cased as required andindividual tubing strings extended to a depth generally slightly aboveeach of the several formation intervals. To isolate these productiveformations from one another, means, such as conventional packers, areemployed to pack-01f the well bore between the casing and tubing stringsnear the upper limit of each of the productive formations. Thus, oncethe tubing strings and these packers arein position, the lower portionof the well bore is divided into a series of vertically spaced, isolatedintervals with only a single tubing string communicating with eachproductive interval and, except for the lowermost interval, throughwhich one or more of the other tubing strings extend to the lowerintervals.

Once this part of the completion operation is finished, the casing must,of course, be perforated adjacent each productive interval to obtaincommunication with the adjacent formations therearound. To accomplishthis, perforating apparatus, such as shaped charges mounted onexpendable supports or confined within retrievable enclosed carriers, issuccessively lowered through each of the tubing strings in turn. Uponreaching the productive interval in which that particular tubing stringterminates, the apparatus is lowered below the lower open end of thestring into the isolated interval and then actuated.

It will be appreciated, however, that, in all but the lowermost of theseproductive intervals, the perforating apparatus must also be laterallydirected to avoid perforating the other tubing strings passing throughthat interval to other intervals therebelow. Accordingly, it has beennecessary heretofore to employ such arrangements as pre-positionedguides on the tubing strings that cooperatively engage and orient theperforating apparatus to direct its axis of perforation away from theadjacent tubing strings passing through that productive interval.

Typical of such orienting arrangements i that shown in the LebourgPatent No. 3,168,141 wherein tubular subs having an enlarged, eccentricor offset portion are coupled to the lower end of all but the longeststring before the tubing is placed in the well. To ensure that theoffset portions of these locating subs are correctly aligned withrespect to the adjacent strings, the tubing strings must be firmlysecured to one another and lowered as a group into the well. Then, aperforator having an extendible orienting arm is successively positionedin each tubing string and manipulated until the extendible arm entersthe olfset portion of the locating sub for that string to direct theperforator away from the adjacent strings. Although such arrangements asthat shown in the Lebourg patent have been successfully employed, itwill be recognized that it is not always desirable or possible topre-position these locating subs. It is also particularly time-consumingand generally more expensive to run two or more pipe strings into a wellsimultaneusly. Moreover, once such locating subs are installed, they canbe somewhat of an obstacle to passage of other tools as well as of noutility should it later be desired to perforate the well at asubstantially different depth.

Accordingly, it is an object of the present invention to provide new andimproved apparatus for orienting a perforator in multiple-completionwells without such prepositioned guides that positively preventspremature actuation of the perforator until it is directed away fromadjacent tubing strings as well as subsequently facilitates thewithdrawal of the perforating apparatus.

This and other objects of the present invention are accomplished byconnecting to a perforator having a selected lateral direction ofperforation a normally-retracted orienting arm having a wall-engagingportion that is extendible to a position substantially diametricallyopposite the direction of perforation-Means are provided for selectivelyextending the orienting arm with sufficient force after the perforatorhas emerged from the open end of a pipe string to shift the perforatorlaterally in the direction it is to perforate. Disabling means areprovided to deactivate the perforators perforating devices until theorienting arm has extended a minimum distance representative of asubstantial proportion of the well bore diameter at the depth ofperforation. Thus, by rendering the perforating devices inoperativeuntil the orienting arm has been extended at least this minimumdistance, the perforator cannot be actuated until its direction ofperforation is faced away from adjacent tubing strings. Means arefurther provided for subsequently retracting the orienting arm once theperforator has been fired to facilitate withdrawal of the perforatingapparatus.

The novel features of the present invention are set forth withparticularity in the appended claims. The present invention, both as toits organization and manner of operation together with further objectsand advantages thereof, may best be understood by way of illustrationand example of certain embodiments when taken in conjunction with theaccompanying drawings, in which:

FIG. 1 is an elevational view showing perforating apparatus includingthe present invention as it may appear in a well bore;

FIG. 2 is a schematic view in plan showing the perforating apparatus ofFIG. 1 in typical positions for perforating;

FIG. 3 is a view similar to FIG. 2 but showing the perforating apparatusin typical undesirable positions;

FIG. 4 is an elevational view in cross-section of one embodiment of theorienting device of the present invention as it will appear in itsinitial operating position;

FIG. 5 is a view of the apparatus of FIG. 4 in another operatingposition;

FIG. 6 is a view of the apparatus of FIG. 4 but illustrating stillanother of its operating positions;

FIG. 7 is a schematic wiring diagram of suitable electrical circuitryfor the apparatus of FIG. 4; and

FIG. 8 is a cross-sectional view of a portion of an alternate embodimentof the present invention.

Turning now to FIG. 1, a representative view is shown of a borehole 10lined with cement Ill to secure a casing 12 extending through productiveearth formations 1315. In the casing 12 is a first tubing string 16depending from conventional wellhead equipment (not shown) at the earthssurface, with its lower open end 17 being terminated just above theuppermost productive earth formation 13. Second and third tubing strings18 and 19 are similarly dependently secured at the surface andrespectively extended through the casing 12 to a depth above the nextlower earth formation 14 and the lower most productive earth formation15. To isolate the productive formations 1315 from the upper portion ofthe well bore 20, a conventional packer 21 is arranged to seal the spacebetween the interior wall of the casing 12 and the outer walls of thetubing strings 16, 18 and 19 above the uppermost formation 13. Anotherconventional packer 22 is arranged between the formations 13 and 14 topack-off the annulus around the longer tubing strings 18 and 19; whilestill another packer 23 may be likewise employed to seal the spacebetween the casing 12 and the longest tubing string 19 between theformations 14 and 15.

To perforate the casing 12 opposite the uppermost earth formation 13,perforating apparatus 24 including a casing-collar locator 25, theorienting and safety device 26 of the present invention and a perforator27, is dependently suspended from an electrical cable 28 spooled from awinch (not shown) at the earths surface and lowered into the tubingstring 16. It will be understood, of course, that although FIG. 1depicts a so-called retrievable perforator 27 which encloses a pluralityof shaped charges (not shOWn) facing closed, lateral ports 29longitudinally aligned along one side of its carrier, other types ofperforators can also be employed so long as their perforating devicesare arranged to fire in substantially the same predetermined lateraldirection. Thus, by directing the lateral direction of perforation ofthe perforator 27 away from both of the adjacent strings 18 and 19, theperforator can be safely actuated to produce a series of longitudinallyspaced perforations (not shown) through the casing 12 and cement 11 intothe earth formation 13.

After the perforating apparatus 24 has emerged from the lower open end17 of the tubing string 16, it is, of course, substantially free torotate or be shifted laterally in any direction with little or norestraint or guidance from the cable 28. Accordingly, as will besubsequently explained in detail, the orienting device 26 of the presentinvention includes means to position the perforator 27 so it can besafely actuated without damaging an adjacent tubing string such as 18and 19. To accomplish this, the orienting device 26 includes an arm 30(FIGS. 2-6) that is laterally movable by a continued force to anextended position diametrically opposite from the ports 29 (FIG. 1).Inasmuch as the perforating apparatus 24 is freely suspended, it will beappreciated that when the arm 30 is forced against one side of thecasing 12, the perforator 27 will be urged toward the opposite side ofthe casing in its lateral direction of perforation 3 1.

' It will be recognized that there are a great number of directions inwhich the perforator 27 can face once it is lowered into an isolatedzone. Thus, as a preliminary to a detailed description of the invention,the various positions that the perforating apparatus 24 can assume areschematically illustrated in FIGS. 2 and 3. For example, the perforatingapparatus 24 can emerge from the lower open end 17 of the tubing string16 with the shaped charges 32 facing away from the adjacent tubingstrings 18 and 19. In this event, the arm 30 will be extended betweenthe adjacent strings 18 and 19 against the casing 12 to urge theperforator 27 into the position depicted in full-line in FIG. 2 with itsdirection of perforation being as shown by arrow 31.

On the other hand, should the shaped charges 32 be initially facing oneof the adjacent tubing strings 18 or 19, as the arm 30 is extended intothe position shown in the dashed lines in FIG. 2, the perforatingapparatus 24 will be urged against that tubing string, as for example,18, When the perforator 27 reaches a position as represented by thedashed lines in FIG. 2, the continued force of the orienting arm 30against the casing 12 will deflect the perforating apparatus 24 somewhattangentially away from the tubing string 18 and in the direction shownby arrow 33. It will be realized that should the arm 38 initially engageone of the tubing strings 18 and 19, the continued force thereon will beeffective to cause it to slide to one side or the other, of that tubingstring. Once the perforating apparatus 24 is against the casing 12, the

perforator 27 may, of course, be safely actuated without damaging theadjacent tubing strings 18 and 19.

It will be recognized, however, that it is not always certain that theperforating apparatus 24 will come to rest in a position where itsdirection of perforation 31 does not intersect one of the adjacenttubing strings 18 and 19. For example, it is quite possible for theperforating apparatus 24 to be urged between both of the adjacent tubingstrings 18 and 19 somewhat as illustrated in fullline in FIG. 3.Similarly, should the outer end 34 of the arm 30 become engaged with anirregularity on the wall of the casing 12, the perforator 27 couldreadily assume a position as shown by the dashed lines in FIG. 3.Although the perforator 27 could possibly be actuated in either of thepositions illustrated in FIG. 3 without damaging the adjacent tubingstrings 18 and 19, it is considered ,too risky to do so.

Accordingly, to be certain that actuation of the perforator 27 willneither damage nor puncture the adjacent strings 18 and 19, theorienting device 26 of the present invention includes means 35 fordisabling the perforator until it is positively facing in a safedirection relative to the adjacent tubing strings. To accomplish this,the disabling means 35 are arranged whereby the perforator 27 cannot beactuated until the extendible arm 30 has moved outwardly a predetermineddistance that can be attained only when the perforating apparatus 24 iseither engaged against the casing 12 or is very near thereto. If, forsome reason, the extendible arm 30 cannot be moved such a distance, itis very likely that the perforator 27 has assumed a position, such asthose in FIG. 3, where its actuation might well damage at least one ofthe adjacent tubing strings 18 or 19. Thus, as will be subsequentlydescribed in greater detail, the disabling means 35 of the presentinvention are made operatively responsive to movement of the extendiblearm 30. By selecting a minimum stroke through which the arm 30 must movein accordance with the geometrical and dimensional parameters of aparticular well bore to avoid an adjacent tubing string, the disablingmeans 35 can be arranged to disarm the perforator 27 until the arm hasreached this predetermined position.

It will be appreciated, of course, that should the perforator 27 beshifted into a position such as those repre sented in FIG. 3, it willnot necessarily remain in such a position. In such an instance, it willbe readily ascertainable, for example, by monitoring conventionalmeasuring equipment (not shown) at the surface that an attempt toactuate the perforator 27 was unsuccessful However, upon determiningthat the perforator 27 was not in fact actuated, repeated reciprocationof the suspension cable 28 will generally suffice to reposition theperforating apparatus 24 to enable the extendible arm 30 to shift theperforator into a safe position. If this is accomplished, the perforator27 will then be armed once the arm 30 has extended the minimumpredetermined strokes previously mentioned. Once the arm 30 has shiftedthe perforator 27 into a safe position, it can, of course, be actuatedupon a second attempt.

After the perforator 27 has been actuated, it is necessary, of course,to retrieve the perforating apparatus 24 by pulling it back through theopen end 17 of the tubing string 16 from which it had previouslyemerged. This may, however, prove to be a significant feat. For example,as best seen in FIG. 1, it is not at all uncommon for one or more of thetubing strings, such as at 19, to be deviated or cork screwed downthrough the casing 12 in a particularly long isolated interval asbetween the widely spaced packers 22 and 23. Thus, as the suspensioncable 28 is being manipulated to bring the perforator 27 into a safefiring position at a selected depth, it is quite possible for the cableto become wrapped at least par- 1 tially around the adjacent tubingstring 19. Should this or similar entanglements occur, it will beappreciated that if the extendible arm 30 were to continually urge theperforating apparatus 24 against the casing '12 below the entanglement,the chances of freeing the cable 28 would be substantially lessened.

Accordingly, as will subsequently be described in greater detail, means36 are provided for selectively retracting the extendible arm 30. Toeliminate the necessity of arranging special electrical circuitry orproviding a separate conductor in the cable 28, the retracting means 36are made responsive to the actuation of the perforator 27. Thus,whenever the perforator 27 is actuated,

the retracting means 36 operate to return the arm 30 to its initialretracted position. With the arm 30 retracted, the perforating apparatus24 will again be freely suspended from the cable 28. Once the apparatus24 is freely suspended, it will be appreciated that a pull on the cable28 will be more likely to maneuver the apparatus around a tubing stringto unwrap the cable therefrom. Similarly, should the cable 28 haveentered a narrow space between the casing 12 and a bend in a tubingstring, as at 19 (FIG. 1), an upward pull on the cable will often slidethe upper end of the apparatus 24 along the adjacent surfaces of thetubing and casing to bring the apparatus free of such an obstruction.

Turning now to FIG. 4, a preferred embodiment is shown of the orientingdevice 26 of the present invention having the above-described means 35and 36. The orienting device 26 includes a tubular housing 37 having anelongated longitudinal slot 38 along one side thereof and closuremembers 39 and 40 at each end of the housing. A tubular sub 41 fluidlysealed by O-rings 42 and secured over the upper end-closure member 39connects the orienting device 26 to the casing-collar locator 25 andsuspension cable 28 (FIG. 1) as well as encloses an electrical switch 43and other electrical components (not shown). Similarly, the lowerend-closure member 40 is fluidly sealed by O-rings 44 and secured withinthe upper end of a tubular perforator carrier 45. Means, such as a keyor set screw 46 inserted through the carrier 45 into the end-closuremember 40, are provided to co-rotatively secure the carrier in a known,fixed radial position relative to the orienting device 26. Thus, as bestseen in FIG. 4, the lateral direction of perforation 31 of the shapedcharges 32 (only one shown) within the carrier 45 is fixed diametricallyopposite from the elongated slot 38 in the housing 37.

The orienting arm 30 is comprised of an elongated member 47 having itsupper end dependently secured to the outer end of a bifurcated arm 48 ofa bell crank 49 and its lower free end 34 curved inwardly and arrangedto be pivoted outwardly and upwardly through the elongated housing slot38. The bell crank 49 is pivotally mounted at its fulcrum by atransverse pin 50 passing through the housing 37 on its opposite sidefrom the elongated slot 38. To reduce the orienting device 26 to aminimum diameter commensurate with the internal diameters of smallertubing strings, the bell crank 49 is arranged with its bifurcated arm 48extending downwardly at an angle from the pivot pin 50 and its other arm51 extending upwardly therefrom a short distance into the housing 37.

T o urge the arm 30 outwardly, an elongated leaf spring member 52 havingend portions 53 and 54 tapering slightly from an enlarged centralportion 55 is extended longitudinally within the housing 37 parallel toand opposite from the slot 38, with the central portion being confinedtherein between a transverse pin 56 through the housing and the insidesurface of the housing wall 57 opposite the slot. The upper end portion53 of the spring member 52 is flexed inwardly slightly toward the slot38 and passed through the bifurcated crank arm 48 where its upper end 58is engaged with the rounded upper end 59 of the shorter crank arm 51. Ascrew 60 through the lower end portion 54 of the spring member 52 hasits head confined within a recess 61 in the inner surface of the housingwall 57 to provide an adjustment for the spring member.

Thus, when the orienting arm 30 is in the retracted position depicted inFIG. 4, the spring 52 will impose an outwardly directed lateral force 62on the upper end 59 of the shorter crank arm 51, which force will tendto rotate the orienting arm 30 outwardly in a counterclockwise directionaround its pivot 50. It will be appreciated that as the adjustment screw60 is unthreaded, the lower end portion 54 of the spring 52 will beshifted inwardly. Accordingly, as its lower end portion 54 is movedfurther under the transverse pin 56, the spring 52 will be flexed stillfurther and, thereby, further increase the lateral force 62 actingoutwardly on the crank arm end 59.

The disabling means 35 include the electrical switch 43 that isappropriately mounted in the tubular sub 41 to align its actuator 63with a longitudinal bore 64 through the upper end-closure member 39. Arod 65 having its upper end slidably received within a conventionalstuffing box 66 through the longitudinal bore 64 is threadedly connectedat its lower end to a transverse member 67 loosely confined within slots68 on the opposed sides of the bifurcated crank arm 48. A contact pin 69is slidably received within a blind coaxial bore in the upper end of theactuating rod 65 and normally urged upwardly by a spring (not shown)within the blind bore. To vary the spacing between the switch actuator63 and upper end of the contact pin 69, an adjusting wheel 70 isslidably mounted around a square central portion 71 of the actuating rod65 above the threads 72 at its lower end. The opposite peripheral edgesof the adjusting wheel 70 are confined within lateral circumferentialgrooves 73 on opposite sides of the housing 37. Thus, by rotating theadjusting wheel 70 in the appropriate direction, the actuating rod 65may be-shifted either upwardly or downwardly through the wheel toposition the contact pin 69 as desired in relation to the switchactuator 63.

To restrain the orienting arm 30 in its retracted position illustratedin FIG. 4, releasable latching means 74 are provided. The latching means74 includes a pivotally mounted latch 75 having a notch 76 on one end 77thereof that receives the lower end 34 of the orienting arm 30.Releasing means, such as an electrically initiated explosive squib 78having a rigid body engaged between the other end 79 of the latch 75 andlower end-closure mem ber 40, are provided to prevent the latch fromrotating about its pivot pin 80 until it is desired to release theorienting arm 30. To detonate the squib 78, an electrical conductor 81is confined within a sealed conduit 82 that extends between the upperand lower closure members 39 and 40. As will be subsequently described,the conductor 81 is connected to the squib 78 to permit its selectivedetonation upon command from the surface.

Thus, as best seen in FIG. 4, so long as the latch 75 is prevented fromrotating by the squib 78, the lower end 34 of the extendible arm 30 willbe confined within the latch notch 76 and cannot be extended. With thearm 30 in this position, the actuating rod 65 is adjusted so that thecontact pin 69 does not engage the switch actuator 63.

To release the extendible arm 30, it is only necessary to detonate thesquib 78. As best seen in FIG. 5, upon detonation of the squib 78, itsupper portion is disintegrated thereby freeing the pivotal latch 75 forclockwise rotation. Once the latch 75 is freed, the laterally directedforce 62 from spring 52 against the outer rounded end 59 of the bellcrank 49 will rotate the orienting arm 30 in a counterclockwisedirection around its pivot 50. As the free arm end 34 swings upwardlyand outwardly, the transverse member 67 will shift the actuating rod 65longitudinally upwardly. It will be realized, of course, that the loosefit of the transverse member 67 within the opposed slots 68 permits theactuating rod 65 to move smoothly in a longitudinal direction as thebifurcated crank arm 48 pivots. By properly adjusting the wheel 70,

the contact pin 69 is positioned to depress the switch actuator 63whenever the extendible arm 30 has reached a predetermined extendedposition. Then, should the extendible arm 30 move further outwardly, thespringloaded contact pin 69 will maintain the actuator 63 depressed butwill not be forced further upwardly to possibly damage the switch 43.

Turning now to the selectively operable means 36 for retracting theextendible arm 30. As best seen in FIG. 4, the lower closure member 40is bored from its opposite ends to provide a pair of longitudinal blindbores 83 and 84. The bores are interconnected by a longitudinal passage85 extending from the blind end of the lower bore 84 to an intersectionwith a transverse passage 86 that joins the upper portion of the upperbore 83 and is closed at its outer end by a suitable closure member 87.If desired, the closure member 87 may be arranged to serve as a flowrestrictor to regulate the flow rate through the passages 85 and 86. Aslidable piston member 88 is fluidly sealed within the lower bore 84 byan O-ring 89 and confined therein by a suitable stop member 90 at thebores lower end. A second slidable piston member 91, fluidly sealedwithin the upper bore 83 by an O-ring 92, has a piston rod 93 extendingupwardly therefrom and through a stuffing box 94 sealingly fitted intothe upper end of the upper bore 83.

A follower rod 95 couples the upper, exposed end of the piston rod 93 toa clevis 96 that is slidably confined within opposed grooves 97 onopposite sides of the housing 37. The spaced arms of the clevis 96 areextended upwardly around the bifurcated crank arm 48 and support theopposite ends of the transverse member 67. Thus, it will be appreciatedthat whenever the bell crank 49 pivots to swing the extendible arm 30outwardly and draw the clevis 96 upwardly, the follower rod 95 andpiston rod 93 will pull the piston 91 upwardly.

Accordingly, when the longitudinal bores 83 and 84 and interconnectingpassages 85 and 86 are filled with a suitable hydraulic fluid 98, itwill be appreciated that as the piston 91 is pulled upwardly, fluid willbe displaced from the upper bore 83 through the interconnecting passagesand into the lower bore 84. As the hydraulic fluid 98 is displaced intothe lower bore 84, the lower piston 88 will be forced downwardly adistance that is proportionately related to the lateral distance whichthe extendible arm 30 swings outwardly. Conversely, it will also berealized that by forcing the lower piston 88 upwardly to its initialposition, the upper piston 91 will be returned to its initial positionas the hydraulic fluid 98 is displaced back into the upper bore 83.

It will be appreciated that the interior of the carrier 45 will remainat substantially atmospheric pressure so long as it is not opened, as bythe shaped charges 32 puncturing holes therein upon their successfuldetonation. Moreover, as the piston member 91 is drawn upwardly by theextension of the arm 30, the space 99 (FIG. below the piston will be ata slightly sub-atmospheric pressure. Accordingly, as best seen in FIG.6, whenever the shaped charges 32 in the sealed carrier 45 aredetonated, fluids 100 in the well bore 20 (FIG. 1) will be admittedthrough the perforated carrier wall to impose their pressure against theunderside of the piston member 88 and force it upwardly.

As the fluids 100 in the well bore 20 force the lower piston 88upwardly, the hydraulic fluid 98 will be displaced from the lower pistonbore 84 and back into the upper piston bore 83 by way of theinterconnecting passages 85 and 86 to force the upper piston 91downwardly to its initial position. As the upper piston 91 movesdownwardly, the piston rod 93 will, of course, return the follower rod95 and clevis 96 to their initial positions. As the clevis 96 movesdownwardly, the transverse member 67 will restore the actuating rod 65as well as the bell crank 49 to their original positions. It will berecognized, of course, that the lower piston 88 and hydraulic fluid 98could be omitted and allow the well fluids to enter the upper pistonbore 83 instead. This is not desirable, however, inasmuch as it would benecessary to clean the retracting means 36 after each operation.

To resecure the arm 30 in its retracted position, a flat leaf spring 101is secured at one end within the housing 37 by a transverse pin 102 andhas an inwardly hooked free end 103 engaging the pivotal latch end 77adjacent to the arm-retaining notch 76. By bowing the latch spring 101over a second transverse housing pin 104 intermediate of the springends, the spring is flexed to urge the hooked spring end 103 against thelatch end 77'. Thus,

as the extendible arm 30 is retracted, its lower end 34 will reenter thenotch 76 on the pivotal latch 75 to restore the latch to its initialposition.

The continued application of hydrostatic pressure will displace theupper piston member 91 until it has reached the bottom of the upperpiston chamber or bore 83. It will be noted by comparison of FIGS. 2 and6, that the piston member 91 will return to a final position slightlylower than the position it initially occupied as in FIG. 4. Thisslightly increased displacement of the upper piston member 91 will, ofcourse, pull the interconnecting linkage elements further downwardlythan initially positioned to bring the lower end 34 of the orienting arm30- inwardly a slight distance further than originally. Thus, as thelower free end 34 of the orienting arm 30 moves inwardly this slightincreased distance, the pivotal latch 75 will be rotated suflicientlyfor the hooked free end 103 of the latch spring 101 to receive the noseof the upper latch arm 77 and latch it against further rotation. It willbe appre ciated, therefore, that once the hooked free end 103 of thelatch spring 101 is engaged over the nose of the pivotal latch arm 77,the extendible arm 30 will be firmly secured in its retracted positionto permit the perforating apparatus 24 to be freely manipulated asrequired to retrieve it in the manner already described.

It should be especially noted that the outer end 59 of the bell crank 49is preferably shaped in such a manner that the eflective moment arm onwhich the lateral spring force 62 is applied will increase as theextendible arm 30 swings further outwardly. Thus, inasmuch as thelateral force 62 of the spring 52 will decrease as it approaches itsrelaxed position, the effective moment arm on which the laterallydirected spring force is acting is increased so as to move theextendible arm 30 outwardly with a force 105 (FIG. 5) that is somewhatconstant. Thus, even though the force 62 applied to the short crank arm51 will decrease as the extendible arm 30 approaches the end of itsstroke, the increased length of the moment arm will insure that theoutwardly directed force 105 that is available on the free end 34 of theextendible arm will always be suflicient to displace the perforatingapparatus 24 laterally in the diametrically opposite direction.

Turning now to FIG. 7, a wiring diagram is shown of a typical firingcircuit that may be employed with the perforating apparatus 24. Thecentral conductor 106 of the cable 28 is divided and connected to thecommon contact 107 of the switch 43 and to a polarity-responsive device,such as a diode 108. The opposite end of the diode 108 is connected byconductor 81 to the initiator of the explosive squib 78. Thus, whenevera positive voltage is applied to the central conductor 106, theexplosive squib 7 8 Will be detonated. This, as previously described,releases the orienting arm 30. Then, whenever the orienting arm 30 hasbeen extended a suflicient distance to permit the actuating rod 65 toclose the switch 43, the central conductor 106 will be connected throughthe switch to another diode 109 oppositely poled to the other diode 108.Whenever a negative voltage is applied to the central conductor 106,current will flow therefrom by a conductor 110 to a conventionalblasting cap 111 for detonating the shaped charges 32 in the usualmanner. It should be noted that, if desired, the switch 43 could also besuitably arranged to provide a visual indication at the surface wheneverthe orienting arm '30 has been sufficiently extended to insure that theperforator 27 is safely positioned.

Turning now to FIG. 8, an alternate embodiment is shown of the lowermostportion of an orienting device 26 that is suitably arranged to employthe present invention with a perforator comprised of encapsulated shapedcharges (not shown) that are supported from an expendable support 112,such as those shown in Patent Nos. 3,048,101 or 3,100,443, and havingthe charges facing generally in one lateral direction. It will berecognized that Where such expendable supports are used, the fluids inthe well are in contact with the shaped charges. Thus, to permit theorienting device 26' of the present invention to be used with suchperforat-ors, the bottom of the lower end-closure member 40' issealingly enclosed by a frangible cap 113 having a weakened portion 114adjacent to the open end of the lower bore 84. Then, by extending thedetonating cord 115 to within close proximity of the cap 113, upondetonation of the detonating cord, the weakened portion 114. will befractured to admit fluids in the well into the lower end of the pistonbore 84. The orienting device 26' is otherwise arranged in the samemanner as that shown at 26 in FIGS. 4-6.

Turning now to the operation of the orienting device 26. FIGS. 4-6 showthe successive positions of the orienting device 26 as the perforatingapparatus 24 is manipulated in the manner already described withreference to FIGS. 13. Prior to placing the apparatus 24 into a tubingstring such as 16 (FIG. 1), the adjustment wheel 70 is rotated to bringthe actuating rod 65 into a proper spatial relation with the switchactuator 63. By knowing the diameters of the casing 12 and the smallestof the other tubing strings 18 or 19 therein at the depth ofperforation, this spatial relation can be adjusted where the switch 43will not be closed until the arm 30 has moved to a predeterminedextended position. It will be appreciated that until the free arm end 34can so move that it is laterally spaced from the opposite housing wall57 a distance at least slightly greater than shown in fullline in FIG.3, it is best not to risk actuating the perforator 27. Thus, bypredetermining what maximum stroke of the orienting arm 30 might stillbe possible with the apparatus 24 in the full-line position shown inFIG. 3, the actuating rod 65 may be readily adjusted to leave the switch43 open until the arm is unquestionably extended a safe distance.

Accordingly, it will be recognized that FIG. 4 illustrates the orientingdevice 26 as it will appear until such time that the orienting arm 30has been released. In this position, the orienting arm 30 is fullyretracted to enable the orienting device 26 to pass freely through atubing string, such as at 16 in FIG. 1. So long as the explosive squib78 is not detonated, the pivotal latch 75 secures the orienting arm 30in its retracted position which, in turn, holds both the actuating rod65 as Well as the piston 91 in their lowermost positions. Once theperforating apparatus 24 emerges from the lower, open end 17 of thestring 16 and has reached the approximate depth for perforating, thesquib 78 is detonated. This frees the pivotal latch 75 and enables thespring 52 to urge the extendible arm 30 outwardly until it has reachedeither an adjacent tubing string 18 or 19 or the internal Wall of thecasing 12.

As the arm 30 swings outwardly, the linkage interconnecting it to thepiston rod 93 pulls the piston 91 upwardly and displaces hydraulic fluid98 from the piston bore 83 to shift the other piston 88 downwardly intothe position shown in FIG. 5. If, perchance, the perforating apparaus 24is fortuitously positioned as illustrated in FIG. 2, the arm 30 will, ofcourse, swing outwardly a sufficient distance to close the switch 43.Nevertheless, so long as the orienting arm 30 has not moved outwardly asuflicient distance calculated to insure that the perforator 27 is notin an undesired position, as in FIG. 3, the actuating rod 65 will nothave shifted upwardly a suflicient distance to actuate the switch 43.Accordingly, as previously explained, so long as the switch 43 remainsopen, the firing circuit to the shaped charges 32 remains open therebypreventing their detonation.

Once, however, the perforating apparatus 24 has been sufficientlymanipulated for the extendible arm 30 to move the perforator 27 intoengagement with the casing 12, the contact pin 69 will depress theswitch actuator 63 to close the switch 43.

As already described, once the perforating apparatus 24 has beenpositioned where its lateral direction of perforation 31 is directedaway from an adjacent tubing string, the perforator 27 may be safelyactuated. Once the shaped charges 32 are detonated, the sealed carrier45 will be .punctured by the resultant perforating jets to admit fluidsin the well bore. As these fluids rush into the carrier 45, the piston88 will be bottomed in the bore 84 and, by operation of the other piston91 and interconnecting link age, retract the arm 30. Once the arm 30 hasreturned sufficiently to allow the latch spring 101 to hook the nose 77of the pivotal latch 75, the free end 34 of the arm will be secured inthe position seen in FIG. 6. Then, With the arm 30 secured, theperforating apparatus 24 is free of any lateral restraint to facilitateits successful return into the lower, open tubing end 17 and saferecovery.

The alternate embodiment 26 depicted in FIG. 8 will, of course, operatein the same manner. Upon detonation of the encapsulated shaped chargestherebelow, the detonation of the extension of the detonating cord willfracture the weakened portion 114 of the frangible cap 113 to admitfluids from the well into the lower portion of the piston bore 84. Oncethese fluids enter the piston bore 84, the orienting device 26' willfunction as already described.

Accordingly, it will be appreciated that the present invention hasprovided means for positively orienting a perforator having a selectedlateral direction of perforation in such a manner that the perforatorwill be positively directed away from an adjacent tubing string.Moreover, the perforator will be positively disabled until such timethat it faces in a safe direction. Then, once the perforator isactuated, the present invention provides means for subsequentlyretracting the orienting arm to facilitate the withdrawal of theperforating apparatus.

While particular embodiments of the present invention have been shownand described, it is apparent that changes and modifications may be madewithout departing from this invention in its broader aspects; and,therefore, the aim in the appended claims is to cover all such changesand modifications as fall within thetrue spirit and scope of thisinvention.

What is claimed is:

1. For use in a well bore including first and second pipe strings ofunequal length terminating at vertically displaced intervals,perforating apparatus adapted for pas sage through the shorter of thepipe strings comprising: perforating means having a selected lateraldirection of perforation; orienting means on said perforating apparatusand laterally movable with respect thereto between a normal retractedposition permitting passage of said perforating apparatus through theshorter string and an extended position against an opposing surface in awell bore diametrically opposite said direction of perforation; meansfor moving said orienting means to said extended position; and means onsaid perforating apparatus for returning said orienting means to saidretracted position.

2. For use in a well bore including first and second pipe strings ofunequal length terminating at vertically displaced intervals,perforating apparatus adapted for passage through the shorter of thepipe strings comprising: perforating means having a selected lateraldirection of perforation; orienting means movably connected to saidperforating apparatus and laterally movable with respect thereto betweena normal retracted position permitting passage of said perforatingapparatus through the shorter string and an extended position against anopposing surface in a well bore diametrically opposite said direction ofperforation; means for moving said orienting means to said extendedposition to urge said perforating apparatus in said direction ofperforation; and means responsive to actuation of said perforating meansfor returning said orienting means to said retracted position.

3. For use in a well bore including first and second pipe strings ofunequal length terminating at vertically displaced intervals,perforating apparatus adapted for passage through the shorter of thepipe strings comprising: electrically-detonated perforating means havinga selected lateral direction of perforation; orienting means movablyconnected to said perforating means and laterally movable with respectthereto between a normal retracted position permitting passage of saidperforating apparatus through the shorter string and an extendedposition diametrically opposite said direction of perforation; means formoving said orienting means to said extended position against anopposing surface in a well bore to urge said perforating apparatus insaid direction of perforation; switch means for disabling saidperforating means until said orienting arm has moved to said extendedposition; and means responsive to actuation of said perforating meansfor returning said orienting means to said retracted position.

4. For use in a well bore including first and second pipe strings ofunequal length terminating at vertically displaced intervals,perforating apparatus adapted for passage through the shorter of thepipe strings comprising: a perforator including perforating means havinga selected lateral direction of perforation; an orienting arm movablyconnected to said perforator and laterally movable with respect theretobetween a normal retracted position permitting passage of saidperforating apparatus through the shorter string and an extendedposition diametrically opposite said direction of perforation; means formoving said orienting arm to said extended position; and means forreturning said orienting arm to said retracted position including aportion of said apparatus having a bore therein, a piston slidablydisposed in said bore and fluidly sealed therein to define a sealedspace in said bore on one side of said piston, means connecting saidpiston to said orienting arm, and means responsive to actuation of saidperforator for admitting well pressure into said bore on the other sideof said piston to move said piston and retract said orienting arm.

5. For use in a well bore including first and second pipe strings ofunequal length terminating at vertically displaced intervals,perforating apparatus adapted for passage through the shorter of thepipe strings comprising: a perforator including perforating means havinga selected lateral direction of perforation; an orienting arm movablyconnected to said perforator and laterally movable with respect theretobetween a normal retracted position permitting passage of saidperforating apparatus through the shorter string and an extendedposition diametrically opposite said direction of perforation; means formoving said orienting arm to said extended position; and means forreturning said orienting arm to said retracted position including aportion of said apparatus having a bore therein, a piston slidablydisposed in said bore and fluidly sealed therein to define a sealedspace in said bore on one side of said piston, means connecting saidpiston to said orienting arm, and means normally preventingcommunication of well bore pressure into said bore and opened bydetonation .of said perforating means to admit such pressure into saidbore on the other side of said piston to move said piston and retractsaid orienting arm.

6. For use in a well bore including first and second pipe strings ofunequal length terminating at vertically displaced intervals,perforating apparatus adapted for passage through the shorter of thepipe strings comprising: a perforator including electrically-detonatedperforating means having a selected lateral direction of perforation;

an orienting arm movably connected to said perforator and laterallymovable with respect thereto between a normal retracted positionpermitting passage of said perforating apparatus through the shorterstring and an extended position diametrically opposite said direction ofperforation; means for moving said orienting arm to said extendedposition; switch means for disabling said perforating means until saidorienting arm has moved to said extended position; and means forreturning said orienting arm to said retracted position including aportion of said apparatus having a bore therein, a piston slidablydisposed in said bore and fluidly sealed therein to define a sealedspace in said bore on one side of said piston, means connecting saidpiston to said orienting arm, and means normally preventingcommunication of well bore pressure into said bore and opened bydetonation of said perforating means to admit such pressure into saidbore on the other side of said piston to move said piston and retractsaid orienting arm,

7. For use in a well bore including first and second pipe strings ofunequal length terminating at vertically displaced intervals,perforating apparatus adapted for passage through the shorter of thepipe strings comprising: a body having a bore therein; encapsulatedshaped charge means having a selected lateral direction of perforationconnected to said body; orienting means movably mounted on said body andlaterally movable between a retracted position permitting passage ofsaid perforating apparatus through the shorter string and an extendedposition against an opposing surface in the well bore diametricallyopposite said direction .of perforation; means for moving said orientingmeans to said extended position; and means for returning said orientingmeans to said retracted position including a slidable piston fluidlysealed in said bore and defining a sealed space therein on one side ofsaid piston, means connecting said piston to said orienting means,passage means between said bore on the other side of said piston and theexterior of said body, means releasably sealing said passage means, andexplosive means between said shaped charge means and passage-sealingmeans for releasing said passage-sealing means upon detonation of saidshaped charge means to admit well bore pressure into said passage means.

8. For use in a well bore including first and second pipe strings ofunequal length terminating at vertically displaced intervals,perforating apparatus adapted for passage through the shorter of thepipe strings comprising: a body having a bore therein; encapsulatedshaped charge means having a selected lateral direction of perforationconnected to said body; an orienting arm pivotally mounted to said bodyand having a free end arranged to move laterally between a retractedposition adjacent to said body and an extended position against anopposing surface in the well bore diametrically opposite said directionof perforation; spring means urging said orienting arm toward saidextended position; means releasably holding said orienting arm in saidretracted position and selectively operable to release said orientingarm; and means for returning said orienting arm to said retractedposition including a slidable piston fluidly sealed in said bore anddefining a sealed space therein on one side of said piston, meansconnecting said piston to said orienting arm, passage means between saidbore on the other side of said piston and the exterior of said body,means releasably sealing said passage means, and explosive means betweensaid shaped charge means and passage-sealing means for releasing saidpassage-sealing means upon detonation of said shaped charge means toadmit well bore pressure into said passage means.

9. For use in a well bore including first and second pipe strings ofunequal length terminating at vertically displaced intervals,perforating apparatus adapted for passage through the shorter of thepipe strings comprising: a body having abore therein; encapsulatedshaped charge means having a selected lateral direction of perforationconnected to said body; an orienting arm pivotally mounted to said bodyand having a free end arranged to move laterally between a retractedposition adjacent to said body and an extended position against anopposing surface in the well bore diametrically opposite said directionof perforation; spring means urging said orienting arm toward saidextended position; means releasably holding said orienting arm in saidretracted position and selectively operable to release said orientingarm; means for returning said orienting arm to said retracted positionincluding a first slidable piston fluidly sealed in said bore anddefining a sealed space therein on one side of said piston, meansconnecting said piston to said orienting arm, passage means between saidbore on the other side of said piston and the exterior of said body, asecond slidable piston fluidly sealed in said passage means and defininga fluid-tight chamber between said pistons, hydraulic fluid filling saidfluid-tight chamber, means releasably sealing said passage means betweensaid second piston and body exterior, and explosive means between saidshaped charge means and passage-sealing means for releasing saidpassage-sealing means upon detonation of said shaped charge means toadmit well bore pressure into said passage means and shift said pistons;and latching means for securing said orienting arm upon its return tosaid retracted position.

10. For use in a Well bore including first and second pipe strings ofunequal length terminating at vertically displaced intervals,perforating apparatus adapted for passage through the shorter of thepipe strings comprising: a body having a bore therein;electrically-detonated encapsulated shaped charge means having aselected lateral direction of perforation connected to said body; anorienting arm pivotally mounted to said body and having a free endarranged to move laterally between a retracted position adjacent to saidbody and an extended position against an opposing surface in the wellbore diametrically opposite said direction of perforation; spring meansurging said orienting arm toward said extended position; meansreleasably holding said orienting arm in said retracted position andselectively operable to release said orienting arm; switch means fordisabling said shaped charge means until said orienting arm has moved tosaid extended position; means for returning said orienting arm to saidretracted position including a first slidable piston fluidly sealed insaid bore and defining a sealed space therein on one side of saidpiston, means connecting said piston to said orienting arm, passagemeans between said bore on the other side of said piston and theexterior of said body, a second slidable piston fluidly sealed in saidpassage means and defining a fluid-tight chamber between said pistons,hydraulic fluid filling said fluid-tight chamber, means releasablysealing said passage means between said second piston and body exterior,and explosive means between said shaped charge means and passage-sealingmeans for releasing said passagesealing means upon detonation of saidshaped charge means to admit well bore pressure into said passage meansand shift said pistons; and latching means for securing said orientingarm upon its return to said retracted position.

11. For use in a well bore including first and second pipe strings ofunequal length terminating atvertically displaced intervals, perforatingapparatus adapted for passage through the shorter of the pipe stringscomprising: a sealed carrier; shaped charge means in said carrier andhaving a selected lateral direction of perforation intersecting a wallof said carrier; orienting means movably mounted on said perforatingapparatus and laterally movable with respect thereto between a normalretracted position permitting passage of said perforating apparatusthrough the shorter string and an extended position against an opposingsurface in a well bore diametrically opposite said direction ofperforation; means for moving said orienting means to said extendedposition to urge said perforating apparatus in said direction ofperforation; and hydraulic means responsive to entrance of fluid intosaid carrier upon perforation of said carrier wall by said shaped chargemeans for returning said orienting means to said retracted position.

12. For use in a well bore including first and second pipe strings ofunequal length terminating at vertically displaced intervals,perforating apparatus adapted for passage through the shorter of thepipe strings comprising: a sealed carrier; shaped charge means in saidcarrier and having a selected lateral direction of perforationintersecting a wall of said carrier; a body having a bore therein andconnected to said carrier; orienting means movably mounted on said bodyand laterally movable between a retracted position permitting passage ofsaid perforating apparatus through the shorter string and an extendedposition against an opposing surface in the well bore diametricallyopposite said direction of perforation; means for moving said orientingmeans to said extended position; and means for returning said orientingmeans to said retracted position including a slidable piston fluidlysealed in said bore and defining a sealed space therein on one side ofsaid piston, means connecting said piston to said orienting means, andpassage means between said bore on the other side of said piston and theinterior of said carrier.

13. For use in a well bore including first and second pipe strings ofunequal length terminating at vertically displaced intervals,perforating apparatus adapted for passage through the shorter of thepipe strings comprising: a sealed carrier; shaped charge means in saidcarrier and having a selected lateral direction of perforationintersecting a wall of said carrier; a body having a bore therein andconnected to said carrier; an orienting arm pivotally mounted to saidbody and having a free end arranged to move laterally between aretracted position adjacent to said body and an extended positionagainst an opposing surface in the well bore diametrically opposite saiddirection of perforation; spring means urging said orienting arm towardsaid extended position; means releasably holding said orienting arm insaid retracted osition and selectively operable to release saidorienting arm; and means for returning said orienting arm to saidretracted position including a slidable piston fluidly sealed in saidbore and defining a sealed space therein on one side of said piston,means connecting said piston to said orienting arm, and passage meansbetween said bore on the other side of said piston and the interior ofsaid carrier.

14. For use in a well bore including first and second pipe strings ofunequal length terminating at vertically displaced intervals,perforating apparatus adapted for passage through the shorter of thepipe strings comprising: a sealed carrier, shaped charge means in saidcarrier and having a selected lateral direction of perforationintersecting a wall of said carrier; a body having a bore therein andconnected to said carrier; an orienting arm pivotally mounted to saidbody and having a free end arranged to move laterally between aretracted position adjacent to said body and an extended positionagainst an opposing surface in the well bore diametrically opposite saiddirection of perforation; spring means urging said orienting arm towardsaid extended position; means releasably holding said orienting arm insaid retracted position and selectively operable to release saidorienting arm; means for returning said orienting arm to said retractedposition including a first slidable piston fluidly sealed in said boreand defining a sealed space therein on one side of said piston, meansconnecting said piston to said orienting arm, passage means between saidbore on the other side of said piston and the interior of said carrier,a second slidable piston fluidly sealed in said passage means anddefining a fluid-tight chamber between said pistons, and hydraulic fluidfilling said fluid-tight chamber; and latching means for securing saidorienting arm upon its return to said retracted position.

15. For use in a well bore including first and second pipe strings ofunequal length terminating at vertically displaced intervals,perforating apparatus adapted for passage through the shorter of thepipe strings comprising: a sealed carrier; electrically-detonated shapedcharge means in said carrier and having a selected lateral direction ofperforation intersecting a wall of said carrier; a body having a boretherein and connected to said carrier; an orienting arm pivotallymounted to said body and having a free end arranged to move laterallybetween a retracted position adjacent to said body and an extendedposition against an opposing surface in the well bore diametricallyopposite said direction of perforation; spring means urging saidorienting arm toward said extended position; means releasably holdingsaid orienting arm in said retracted position and selectively operableto release said orienting arm; switch means for disabling said shapedcharge means until said orienting arm has moved to said extendedposition; means for returning said orienting arm to said retractedposition including a first slidable piston fluidly sealed in said boreand defining a sealed space therein on one side of said piston, meansconnecting said piston to said orienting arm, passage means between saidbore on the other side of said piston and the interior of said carrier,a second slidable piston fluidly sealed in said passage means anddefining a fluid-tight chamber between said pistons, and hydraulic fluidfilling said fluidtight chamber; and latching means for securing saidorienting arm upon its return to said retracted position.

16. As a sub-combination, apparatus adapted for connection to a welltool comprising: a body having a longi tudinal opening along one sidethereof; an arm member pivotally mounted at an intermediate point tosaid body and having a free end portion arranged relative to saidopening for movement therethrough between a retracted position withinsaid body and an extended position exterior thereof; spring meansbetween the other end portion of said arm member and said body forurging said free arm portion toward said extended position; meansholding said arm member in said retracted position including a rigidmember detonatable to fracture said rigid member and release said armmember for movement to said extended position; switch means on saidbody; switchactuating means between said switch means and arm member andresponsive to movement of said arm member for operating said switchmeans in one of said arm member positions; arm-retracting meansincluding a slidable piston fluidly sealed in said body, meansconnecting said piston to saidarm member, means fluidly sealing saidconsaid piston;

16 necting means to define an enclosed space between said piston and armmember, and passage means adapted for communicating a pressurediflerential across said piston; and latching means for securing saidarm member upon its return to said retracted position.

17. As a sub-combination, apparatus adapted for connection to a welltool comprising: a body having a longitudinal opening along one sidethereof; an arm member pivotally mounted at an intermediate point tosaid body and having a free end portion arranged relative to saidopening for movement therethrough between a retracted position withinsaid body and an extended position exterior thereof; spring meansbetween the other end portion of said arm member and said body forurging said free arm portion toward said extended position; meansholding said arm member in said retracted position including a latchmember pivotally mounted on said body and movable between anarm-engaging position and an arm-releasing position, a rigid memberbetween said pivotal latch and body holding said latch in saidarm-engaging position, and explosive means adjacent to said rigid memberselectively detonatable to fracture said rigid member and enable saidpivotal latch to move to said arm-releasing position; switch means onsaid body; switch-actuating means between said switch means and armmember and responsive to movement of said arm member for operating saidswitch means in one of said arm member positions; arm-retracting meansincluding a slidable piston fluidly sealed in said body, meansconnecting said piston to said arm member, means fluidly sealing saidconnecting means to define an enclosed space between said piston and armmember, and passage means adapted for communicating a pressuredifferential across and latching means for securing said arm member uponits return to said retracted position including means responsive toretractive movement of said arm member to return said pivotal latch tosaid arm-engaging position and means engageable with said pivotal latchupon its return to said arm-engaging position to resecure said armmember.

References Cited UNITED STATES PATENTS 3,063,372 11/1962 Diebold 4.513,064,571 11/1962 True 175-4.51 3,168,141 2/1965 Lebourg 175-451 CHARLESE. OCONNELL, Primary Examiner.

D. H. BROWN, Examiner.

1. FOR USE IN A WELL BORE INCLUDING FIRST AND SECOND PIPE STRINGS OFUNEQUAL LENGTH TERMINATING AT VERTICALLY DISPLACED INTERVALS,PERFORATING APPARATUS ADAPTED FOR PASSAGE THROUGH THE SHORTER OF THEPIPE STRINGS COMPRISING: PERFORATING MEANS HAVING A SELECTED LATERALDIRECTION OF PERFORATION; ORIENTING MEANS ON SAID PERFORATING APPARATUSAND LATERALLY MOVABLE WITH RESPECT THERETO BETWEEN A NORMAL RETRACTEDPOSITION PERMITTING PASSAGE OF SAID PERFORATING APPARATUS THROUGH THESHORTER STRING AND AN EXTENDED POSITION AGAINST AN OPPOSING SURFACE IN AWELL BORE DIAMETRICALLY OPPOSITE SAID DIRECTION OF PERFORATION; MEANSFOR MOVING SAID ORIENTING MEANS TO SAID EXTENDED POSI-